I have just changed the bushings on a 2011 Five, with a RP23, front had the most play but rear also needed changing.

EDIT I should also add that I left mine far to long, and also had to change the bolts and there is still a tiny amount of play, so I am looking at getting new top hats as well....I will not leave it so long next time.

The rear sees more rotation, so that's probably what he's thinking. Also, if you're still running the original 'top hat' reducers it's worth swapping out for a 'heavy duty' kit from the likes of TF Tuned

It's always the swingarm pivot that goes first for me, the best thing to check is to lift the rear wheel off the ground, or at least take the weight using the top tube, and with your other hand put your index finger on top of the pivot, you should feel it move (slightly).

I have also known worn / loose pivot bearings to give the same symptoms ,,,, Check that your swing arm is central.